The upstream Huangtaiqiao area of the Xiaoqinghe River Basin in Jinan City was selected as the study area and a SWMM-InfoWorks ICM-2D integrated model was constructed to simulate flood processes under rainfall return periods of 5 to 100 a. Multi-source datasets were integrated to reconstruct a 100 m-resolution refined GDP distribution pattern, and an assessment framework was constructed covering four dimensions, including hazard-causing factors, disaster-breeding environment, hazard-bearing bodies, and disaster prevention capacity. A flood risk assessment method combining flood process simulation and refined GDP distribution was proposed. The results showed that under the same rainfall return period, the flood risk in the study area presented a concentric pattern decreasing from the urban center to the periphery. High-risk areas were concentrated in urban trunk roads, relatively high-risk areas covered the downtown with high population density and GDP, and low-risk areas were mainly distributed in the northwest suburbs and southern mountainous areas. With the increase of rainfall return period, the area of high-risk areas expanded from 2.67 km² to 6.49 km², and their spatial distribution expanded from scattered points to urban corridors, while the scope of other risk-grade areas remained relatively stable. Keywords: flood process simulation; GDP distribution pattern; flood risk assessment; the Xiaoqinghe River Basin; Jinan City 〖FL